In an ordinary image forming apparatus such as a printer or a copier, a print sheet is supplied and discharged along a prescribed path with any visible image reproduced thereon while the print sheet is travelling along the path. In an image forming apparatus of this type, a jamming of a print sheet may be caused at any location of the path along which the print sheet is to be transported until the sheet is to be discharged from the apparatus. A printer or a copier which is presently in use is therefore ordinarily equipped with means adapted to detect an occurrence of the jamming of a print sheet and bring the apparatus to a stop and/or display the occurrence of the jamming for warning to the operator.
Such means may include a jam counter which is operative to update its content each time an occurrence of jamming is detected and thus count the number of occurrences of the jamming detected. The content of such a jam counter provides helpful information to, for example, the serviceman who troubleshoots the apparatus for the purpose of remedying the jammed condition.
An image forming apparatus furnished with such a jam counter has however had an important drawback.
In the event jamming is caused in a printer or a copier, the operator of the apparatus will try to eliminate the jammed condition by removing the jammed print sheet out of the apparatus and then re-start the apparatus if he has successfully eliminated the jammed condition. There may however be a case where he could not visually recognize the jammed print sheet remaining within the apparatus and may thus re-start the apparatus with the jammed condition left therein. The jammed print sheet having failed to be removed out of the apparatus, an occurrence of jamming will be for a second time detected from the particular jammed print sheet during the cycle of operation thus re-started. The occurrence of the jamming caused during the previous cycle of operation will thus be counted as the occurrence of jamming caused during the current cycle of operation and accordingly the content of the jam counter will be incremented twice for one and the same occurrence of jamming. In this fashion, there occurs a discrepancy between the number of occurrences of the jamming actually caused and the number of occurrences of the jamming represented by the content of the jam counter. Such a discrepancy provides misleading information to the serviceman troubleshooting the apparatus.
The occurrences of the jamming detected in the past may be counted cumulatively with the content of the jam counter incremented without being reset. To facilitate the serviceman to troubleshoot the apparatus each time he is requested to attend an accident such as typically an occurrence of jamming, it will be more convenient for him to have the content of the jam counter reset to a certain initial state each time he has services the apparatus so that he is enabled to readily remedy the trouble when he attends the apparatus for a second time.
It is, accordingly, an important object of the present invention to provide an image forming apparatus equipped with an improved jam counter which is operative to update its content each time an occurrence of jamming is detected and thus count the number of occurrences of the jamming detected.
It is another important object of the present invention to provide an improved image forming apparatus in which the number of occurrences of the jamming represented by the content of a jam counter is at all times identical with the number of occurrences of the jamming actually caused after the content of the jam counter has been reset.
It is still another important object of the present invention to provide an improved image forming apparatus having a jam counter which will provide truly helpful information to, typically, the serviceman who troubleshoots the apparatus for the purpose of remedying a jammed condition.
Yet, it is still another important object of the present invention to provide an improved image forming apparatus having a jam counter the content of which is to be reset to a certain initial state each time the apparatus is serviced.